>>>I'm just testing to see if this message posts. I've written a few messages in the last week or so that never appeared.
>>>
>>
>>Answering myself, I see that it did. Wonder what happened to the others.
>
>Might it be possible that you previewed first, and since preview now looks so much like a posted message, you forgot to 'Send'?

No, but I think I figured it out. I tend to use the Tab key to navigate here (so that I don't have to reach for the mouse). It used to be that, when typing a message, Tab followed by Enter posted the message. That seems to have changed.